• See Also
  1. Lactose Intolerance
  2. Lactose Tolerance Test
  • Indications
  1. Lactose Intolerance testing
  • Efficacy
  1. Preferred over Lactose Tolerance Test
  2. Test Sensitivity: 90%
  • Technique
  1. Measure baseline breath hydrogen concentration
  2. Patient ingests lactose
    1. Classic: 25 to 50 grams lactose
    2. Physiologic: 12 grams lactose (same as in 8 oz milk)
  3. Measure breath hydrogen concentration in 3 to 8 hours
    1. Increase >20 ppm suggests Lactose Intolerance
  • False Negative causes
  1. Gastrointestinal flora absent (e.g. recent Antibiotics)
  • False Positive causes
  1. Recent Exercise
  2. Aspirin use
  3. Tobacco Smoking
  • References
  1. Powell in Goldman (2000) Cecil Medicine, p. 711